The present invention relates to a yarn winding apparatus of the type having a rotatable turret or revolver which mounts at least one winding spindle, and wherein a contact roll is positioned to rest upon the package being formed on the spindle. The invention also relates to a method of doffing the apparatus.
A winding apparatus of the described type is known, and wherein relative movement between the contact roll and the winding spindle is carried out by the rotation of the revolver as the package diameter increases, note for example from German OS 32 07 375.
In such known winding apparatus, the contact roll is rigidly supported by the machine frame. The winding spindle is mounted on a rocker arm, which is pivotally supported on the revolver, so that the winding spindle can occupy an outer and an inner radial position relative to the revolver. However, this design lacks of the stability which is necessary for high package weights and high yarn speeds.
DE-OS 25 44 773 discloses a winding apparatus, in which the winding spindle is supported in a movable slide. The contact roll is supported in a likewise movable support. The slide of the winding spindle is held by pneumatic cylinders, which are biased by pressure as a function of the movement of the support of the contact roll, thereby compensating for the weight of the slide with the winding spindle and the package. As the package diameter increases, the pressure which is exerted in the cylinders is reduced in such a manner that the slide lowers by its own weight. In so doing, the so-called stick-slip effects are unavoidable.
Likewise, the support of the spindle on a translatorily movable slide creates significant problems with regard to the stability and service life of the slide guidance.
It is accordingly an object of the present invention to provide a yarn winding machine, wherein the spindle is rigidly supported so as to be free of vibrations, and is adapted to be moved in a controlled uniform manner, even with high package weights and high winding speeds.
It is also an object of the present invention to provide an efficient method of doffing an apparatus of the described type.